Locomotive firebox



Aug. 8, 1939. A. w. NELSON LOCOMOTIVE FIREBOX Filed Aug. 2, 1957 Patented Aug. 8, 1939 UNITED STATES PATENT OFFICE 2,168,625 LOCOMOTIVE FIREBOX Application August 2,

7 Claims.

This invention relates to improvements in locomotive fireboxes and it consists of the matters hereinafter described and more particularly pointed out in the appended claims. The term locomotive fireboxes, as herein used, is meant to include all fireboxes of the locomotive boiler type. The fireboxes of this type and with which the invention is more particularly concerned, are those embodying therein circulators of the syphontype and including at least one transverse conduit connected at its ends to opposite side sheet portions of the firebox and a second conduit operatively connected at one end to the first mentioned conduit and operatively connected at its other end in the crown sheet.

Fireboxes of this type, however, as heretofore made are open to certain objections. For instance, the transverse conduit has always been bowed or arched upwardly, the idea being to make it as rigid as possible.

When the firebox is heated and when it cools,

the firebox sheets and syphon expand and contract. Due to the bowed up or arched construction heretofore provided, this action is resisted and there results a direct thrust against the side sheets and considerable movement of the parts at the point of connection between the syphon intake and the side sheets. That is to say, the normal tendency to elongation is strongly resisted, causing the imposition of strains and stresses, which in time require the servicing of the parts. One of the objects of the present invention is to provide an improved firebox of this kind which avoids the disadvantages now inherent therein and to do so without increasing the cost of manufacture or installation thereof.

Another object of the invention is to provide a firebox of this kind wherein the transverse conduit is formed so that it yields or flexes to accommodate the expansion of parts without imposing a detrimental action on the connections betweenthe transverse conduit and side sheet portions 'of the firebox in which its ends are operatively secured.

Still another object of the invention is to provide a construction which will permit the intake ends of the syphon to be secured in the side sheets without a diaphragm plate, thus simplifying the installation and reducing the cost thereof.

The above mentioned objects of the invention, as well as others, together with the advantages thereof, will more fully appear as the specification proceeds.

In the drawing:

1937, Serial No. 156,973

Fig. 1 is a longitudinal vertical sectional view through a locomotive type of firebox embodying the preferred form of the invention.

Fig. 2 is a transverse vertical sectional view through the same, on an enlarged scale, as taken on the line 2-2 of Fig. 1.

Fig. 3 is a top plan View of a certain improved circulator unit or syphon embodied in the firebox and which will be more fully referred to later.

Fig. 4 is a detail view illustrating an alternate method of attaching the ends of the syphon to the side sheets. 1

Referring now in detail to that embodiment of the invention illustrated in the accompanying drawing, the combustion chamber firebox appearing therein includes a crown sheet 5 which merges into the inner side sheets 6, an inner back sheet I and an inner throat sheet 8. As herein shown, the crown sheet extends forwardly of the inner throat sheet to form the top of the combustion chamber 9. This chamber is closed at the front end by a flue sheet Ill and the bot tom ll of said chamber merges into the front end of the inner throat sheet 8.

The outer rear sheet is indicated at l2, the outer side sheets are indicated at l3 and the outer throat sheet is indicated at l4. Said sheets cooperate with the top sheet [5 and the outer side sheets I3 in forming the back water leg IS, the side water legs I? and the front throat l8 respectively, all in communication with the water space IEI of the boiler. water legs and the front throat are bottomed by a mud ring and portions of the inner and outer back sheets are formed to provide a fuel door opening 2|.

Within a part of the firebox is one or more thermic syphons 22, the number thereof being dependent upon the width and length of the firebox. In this instance only one syphon is shown and this is arranged in that part of the firebox to the rear of the inner throat sheet 8. However, a syphon of suitable shape and size could be arranged in the combustion chamber 9, if so desired. In mentioning the side sheets or side sheet portions of the firebox herein, the same is to be understood to include the side walls of the combustion chamber proper.

As herein shown, the syphon includes a sub stantially fiat hollow body 23 of generally a triangularor V shape, disposed in the longitudinal median line of the firebox. The body has a flangedtop 24 fixed in the crown sheet so as to define an outlet or discharge 25 as appears in Figs. 1

and 2. The front and rear end walls for the body The back and side 7 of metallic fatigue.

converge inwardly and downwardly to form the inlet end 26 for the body.

21 indicates a duplex inlet member for the syphon. Said member, as herein shown, is in the form of a transversely extending conduit of such a shape longitudinally that it may flex downwardly under the expansion action, due to increase in temperature in the firebox. As herein shown, said member is in the form of a tube bent to form an inverted arch or the lower part of a circle and its ends are secured in the opposed side sheet portions of the firebox in any suitable manner. Thus the ends may be affixed in the manner illustrated in Figs. 1 and 2. In this construction the neck or ends of the portions 21 are inserted directly into openings in the side sheets. The ends are then flared out slightly as indicated at 28 and butt welded to the side sheets from the firebox side as indicated at 36. In view of the flexing action which the present syphon construction provides this form of attachment Without 2. diaphragm plate is deemed satisfactory as the syphon will move to accommodate the expansion and contraction stresses without imposing a detrimental action on the connections between the syphon necks or intakes and the side sheets.

If desired, however, the alternate construction shown in Fig. 4 may be used. In that construction a diaphragm plate 3| is welded in the side sheet as indicated at 32 and the intake neck or end of the syphon portion 21 is welded to the diaphragm member as indicated at 33.

The end portions of said conduit are fixed in said side sheet portions at an elevation above the mid portion of said conduit which forms the lowest point in the conduit. The inlet end 26 for the body 23 is operatively connected to said mid portion of the body.

Preferably the conduit 21 is made on a curve forming an arc of a circle having its center in the median line of the firebox, a considerable distance above the crown sheet. This curve is of such magnitude that it will not hang too low in the firebox nor overcome the difference in thermic heads between the lower mid portion of the conduit and the higher end portions thereof. Thus,

- ends of the conduit for use in washing out the syphon in boiler washing operations.

It is well known that due to changes in temperature conditions in the firebox, the sheets thereof expand and contract and this is most often manifested perpendicularly in the firebox. With the conduit formed as described, it can flex downwardly, intermediate its ends, without imparting an undue outward pressure on the side sheet portions in which its ends are secured. With such a formation of the conduit, the flexing occurs in the conduit itself so that there is but very little, if any movement, in the side sheet portions in which its ends are secured. With reduced movement at the connection of the syphon conduits and the side sheets, there is less danger As a result, less service is required and longer periods of satisfactory operation results. 7

It is contemplated, though not absolutely essential, that the syphon structure will, at the time of installation, be normally free of strain and stress. Thus, when it freely flexes, upon being heated, and again returns to normal, at no time are abnormally great strains or stresses developed.

The syphon or circulator is of a simple construction and may be applied to fireboxes already in service or built into new ones with but small installation cost. It may be readily made as an article of manufacture.

While in describing the invention, I have re ferred in detail to the form, arrangement and construction of the parts thereof as well as their relation to each other, the same is to be considered only in the illustrative sense so that I do not wish to be limited thereto except as may be spe' cifically pointed out in the appended claims.

I claim as my invention:

1. A locomotive firebox embodying therein a crown sheet and laterally spaced side sheet portions, means providing a conduit arranged transversely of the firebox and opening at its ends through said side sheet portions, and means providing a second conduit opening at one end through the crown sheet and operatively connected at its other end with a part of said first mentioned means at a point between said ends, said first mentioned means being formed longitudinally for relatively free downward flexing upon being heated.

2. A locomotive firebox embodying therein a crown sheet and laterally spaced side sheet portions, means providing a conduit arranged transversely of the firebox and opening at its ends through said side sheet portions at points higher in elevation than a mid portion of said means, and means providing a second conduit opening at one end through the crown sheet and operatively connected at its other end with a mid portion of said first mentioned means and which mid portion is the lowest portion of said first 1nentioned means.

3. A locomotive firebox embodying therein a crown sheet and laterally spaced side sheet portions, means providing a conduit arranged transversely of the firebox and opening at its ends through said side sheet portions at points higher in elevation than a mid portion of said means, and means providing an upright flat hollow conduit which opens at one end through the crown sheet and tapers downwardly in one dimension toward its other end which is operatively connected with a part of the firstmentioned means at a point between its ends.

4. A locomotive firebox embodying therein a crown sheet and laterally spaced side sheet portions, 9. water steaming and circulating element in the firebox comprising a flat hollow body having an elongated top outlet that opens longitudinally through the crown sheet, the front and rear portions of the body tapering inwardly and downwardly toward the bottom inlet end of the body, and a conduit arranged transversely of the firebox and connected at an intermediate point with said inlet for said body, said conduit having end portions extending upwardly and outwardly in opposite directions from said intermediate point V and opening at its ends through said side sheet portions.

5. A locomotive firebox embodying therein a crown sheet and laterally spaced side sheet portions, a conduit having the formation of the lower part of a circle and arranged transversely of the firebox and opening at its ends through said side sheet portions, and a second conduit arranged substantially radially with respect to said first mentioned conduit and opening at its top end through the crown sheet and operatively connected at its bottom end with a mid portion of said first mentioned conduit.

6. A locomotive firebox embodying therein a crown sheet and laterally spaced side sheet portions, a conduit having the formation of the lower part of a circle and arranged transversely of the firebox and opening at its ends through said side sheet portions, and means providing a flat hollow body in the firebox having an elongated top outlet that opens longitudinally through the crown sheet, the front and rear portions of the body tapering inwardly and downwardly toward the bottom inlet end of the body which is connected to a mid portion of the first mentioned conduit.

7. As an article of manufacture, a thermic syphon comprising an upright fiat hollow body having side, front and rear walls arranged to form an elongated open top for said body, said front and rear walls of the body tapering inwardly and downwardly toward the bottom inlet end of the body, and a tubular conduit arranged transversely of the side walls of the body and connected at a 'mid portion to said inlet and having its ends extending upwardly and outwardly in opposite directions therefrom.

ARTHUR WM. NELSON. 

